The main purpose of the proposed research is to determine whether or not neurocognitive differences between boys, with the presence or absence of family history for a alcoholism, are antecedents for predicting the later development of drug use behavior. A sample of two hundred 11-year old boys, who have not yet started to use any drugs, including alcohol, will be rigorously screened and selected for two groups: (1) sons of alcoholic fathers with a positive family history of alcoholism (FH+) and 2) sons of fathers with a negative family history of alcoholism (FH-). Each boy will be assessed as he enters the study and two years later across two neurocognitive dimensions: a) neuropsychological performance and b) electrophysiological measures. Drug use will be obtained longitudinally through questionnaries as each boy enters the study and during three subsequent years of his participation. Finally, from this data, prediction of early drug use will be determined from the best neurocognitive discriminators obtained between the FH+ and FH- sons. A unique feature of this proposal is its concern about the significance of the CNS differences between FH+ and FH- boys for "real world" drug use behavior during early adolescence. On the basis of preliminary research in this laboratory, two separate but interrelated components of CNS function have been selected and will be used in a larger sample to identify neurocognitive differences between FH+ and FH- boys who have not begun to use drugs. The stability of this neurocognitive characterization will be measured through a second assessment two years later. To fill a gap in existing knowledge, the proposal will also undertake a prospective longitudinal description of adolescent drug use in these children. Finally, the potentially most significant goal of this proposal is to develop the first predictive model of adolescent drug use based on those neurocognitive parameters which maximally differentiate FH+ from FH- boys. Such a model could increase the specificity of identifying high risk individuals and improve the efficacy of focused prevention efforts.